Monitoring and Detecting Magnetic Stimulation

ABSTRACT

A method, system, and apparatus for monitoring a magnetic field related to magnetic stimulation may be provided. A system for monitoring a pulsing magnetic field related to magnetic stimulation therapy may include a magnetic stimulation component, a sensor, and a processor. The magnetic stimulation component may be configured to generate the pulsing magnetic field for the magnetic stimulation therapy. The sensor may be configured to generate a signal associated with the pulsing magnetic field. The processor may be configured to estimate a first characteristic associated with a first peak of the signal, estimate a second characteristic associated with a second peak of the signal, and determine a third characteristic of the signal based on the first characteristic and the second characteristic. The processor may be configured to determine whether a failure occurred based on the third characteristic of the signal.

BACKGROUND

A number of medical ailments may be treated and/or diagnosed through theapplication of a magnetic field to an afflicted portion of a patient'sbody. Neurons and muscle cells may be a form of biological circuitrythat carry electrical signals and respond to electromagnetic stimuli.When a conductive wire loop is passed through a magnetic field or is inthe presence of a changing magnetic field, an electric current may beinduced in the wire. The same principle may hold true for conductivebiological tissue. When a changing magnetic field is applied to aportion of the body, neurons may be depolarized and stimulated. Musclesassociated with the stimulated neurons may contract as though theneurons were firing by normal causes.

A nerve cell or neuron may be stimulated in a number of ways, forexample, transcutaneously via transcranial magnetic stimulation (TMS).TMS may use a rapidly changing magnetic field to induce a current on anerve cell, without having to cut or penetrate the skin. The nerve may“fire” when a membrane potential within the nerve rises with respect toits normal negative ambient level of approximately −90 mV, for example,depending on the type of nerve, local pH of the surrounding tissue,and/or peripheral nerve stimulation.

A magnetic stimulation component may be used to produce the rapidlychanging magnetic field inducing a current on a nerve cell. The magneticstimulation component may fail or operate improperly during treatment,which may result in improper treatment for the patient. For example, themagnetic component may appear to operate correctly, but actually may beproducing magnetic field pulses outside of designed devicespecifications, potentially resulting in improper diagnosis and/ortherapy being administered to the patient. Administering an incorrectmagnetic field pulse to a patient can affect the magnetic stimulationdiagnosis and/or treatment adversely. For example, the treatmentprovider may believe that the patient is not responding to thetreatment, when in fact the intended treatment is not being administeredto the patient. Thus, the treatment provider and/or diagnosing clinicianmay be led to make treatment decisions based on faulty information.

SUMMARY

A method, system, and apparatus for monitoring a magnetic field relatedto magnetic stimulation therapy may be provided. A system for monitoringa pulsing magnetic field related to magnetic stimulation therapy mayinclude a magnetic stimulation component, a sensor, and a processor. Themagnetic stimulation component may be configured to generate the pulsingmagnetic field for the magnetic stimulation therapy.

The sensor may be configured to generate a signal associated with thepulsing magnetic field. The signal may include multiple peaks. Thesignal may indicate a voltage signal proportional to a change in thepulsing magnetic field, a current signal proportional to a change in thepulsing magnetic field, and/or the like. The sensor may include one ormore of a conductive coil, a loop having a number of turns based on thepulsing magnetic field, a Hall sensor, a magnetoresistive material, aFaraday effect sensor, a Kerr effect sensor, a flux gate sensor, aninductance change element, a nerve tissue response measurement device,an electric field sensor in a conductive field, or the like.

The processor may be configured to estimate one or more characteristicsassociated with one or more peaks of the signal. The characteristics mayinclude a voltage of a peak, a current of a peak, a root mean square(RMS) value of a peak, a zero-cross of a peak, a time value of a peak,and/or a time duration of a peak (e.g., a peak duration). The peak(s)may be associated with a single pulse, consecutive pulses, or separatepulses of the pulsing magnetic field.

The processor may be configured to determine one or more characteristicsassociated with the signal. For example, the processor may determine adecay rate of the signal, a frequency of the signal, a timing associatedwith the signal, a magnetic flux associated with the signal, and/or acurrent associated with the signal, for example, based on the estimatedcharacteristic(s). The processor may be configured to determine whethera failure occurred based on the determined characteristic(s) of thesignal. The failure may be determined to have occurred when thedetermined characteristic(s) is outside of a predetermined acceptancewindow.

The sensor may be configured to generate a voltage induced by a changein the pulsing magnetic field. The processor may be configured toestimate one or more average values of the voltage. An average value maybe associated with one or more sets of pulses of the plurality ofpulses. The average value(s) may include a weighted average value and/oran unweighted average value. The processor may be configured todetermine whether a failure occurred based on the average value(s).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an example of a magneticstimulation system.

FIG. 2 is a block diagram illustrating an example of a magneticstimulation system.

FIG. 3 is a diagram illustrating an example waveform of a signalreceived by a controller of a magnetic stimulation system.

FIG. 4A is a flow diagram illustrating an example procedure fordetermining whether a failure has occurred.

FIG. 4B is a flow diagram illustrating an example procedure fordetermining whether a failure has occurred.

FIG. 5 is a diagram illustrating an example signal of an expectedvoltage induced on a sensor.

FIG. 6 is a diagram illustrating an example signal of a voltage inducedon a sensor that is indicative of a failure.

FIG. 7 is a diagram illustrating an example signal of a voltage inducedon a sensor that is indicative of a failure.

FIG. 8 is a diagram illustrating an example signal of a voltage inducedon a sensor that is indicative of a failure.

DETAILED DESCRIPTION

A system may be provided that monitors a pulsing magnetic field relatedto magnetic stimulation therapy, for example, to determine whether ornot a system failure has occurred. The system may comprise a magneticstimulation component, a sensor, and a processor. The magneticstimulation component may be configured to generate a pulsing magneticfield for performing magnetic stimulation therapy on a patient. Thesensor may be configured to generate a signal associated with thepulsing magnetic field of the magnetic stimulation component. Forexample, the sensor may be placed between the magnetic stimulationcomponent and the patient. In response to the pulsing magnetic field, acurrent signal, a voltage signal, or the like may be generated in thesensor that may be proportional to the pulsing magnetic field.

The processor may be configured to estimate one or more characteristics(e.g., two characteristics) associated with the signal (e.g., thegenerated signal) and determine, based on the estimated characteristics,a characteristic of the signal. The processor may be configured todetermine whether a failure has occurred based on the determinedcharacteristic of the signal. As such, the system may be able to detectwhether the pulsing magnetic field is properly providing magneticstimulation therapy to the patient. Upon detecting a failure, the systemmay be configured to pause the TMS procedure, shut down the magneticstimulation system, alert a user of the magnetic stimulation system,and/or alter a current applied to the magnetic stimulation component.

In 1831, Michael Faraday discovered that the magnitude of an electricfield induced on a conductor is proportional to the rate of change ofmagnetic flux that cuts across the conductor. Faraday's law, well knownto those skilled in the art, may be represented as E˜−(A*dB/dt), where Eis the induced electric field in volts/meter and dB/dt is the time rateof change of magnetic flux density in Tesla/second. In other words, theamount of electric field induced in an object, such as a conductor, maybe determined using two factors: the magnetic flux density and the timerate of change of the flux. The greater the flux density and itsderivative, the greater the induced electric field and resulting currentdensity. Magnetic flux may be a function of distance. For example,because the magnetic flux density may decrease in strength with relationto the distance from the source of the magnetic field (e.g., 1/r³, 1/r⁵,or the like), the flux density may be greater the closer the conductoris to the source of the magnetic field. When the conductor is a coil,the current induced in the coil by the electric field may be increasedin proportion to the number of turns of the coil.

An overview of an example operation and application of a magnetic systemin which aspects of the various embodiments may be implemented may beprovided. The magnitude of an electric field induced on a conductor maybe proportional to the rate of change of magnetic flux density acrossthe conductor. When an electric field is induced in a conductor, theelectric field may create a corresponding current flow in the conductor.The current flow may be in the same direction of the electric fieldvector at a given point. The peak electric field may occur when the timerate of change of the magnetic flux density is the greatest and maydiminish at other times. During a magnetic pulse, the current may flowin a direction that tends to preserve the magnetic field (e.g., Lenz'sLaw).

Certain parts of the anatomy (e.g., nerves, tissue, muscle, brain) mayact as a conductor and may carry electric current when an pulsedmagnetic field is applied. The pulsed magnetic field may be applied tothese parts of the anatomy transcutaneously. For example, in the contextof TMS, a time-varying magnetic field may be applied across the skull tocreate an electric field in the brain tissue, which may produce acurrent. If the induced current is of sufficient density and/orduration, neuron action potential may be reduced to the extent that themembrane sodium channels open and an action potential response iscreated. An impulse of current may be propagated along the axon membranethat transmits information to other neurons via modulation ofneurotransmitters. Such magnetic stimulation may acutely affect glucosemetabolism and local blood flow in cortical tissue. In the case of majordepressive disorder, neurotransmitter dysregulation and abnormal glucosemetabolism in the prefrontal cortex and the connected limbic structuresmay be a likely pathophysiology. Repeated application of magneticstimulation to the prefrontal cortex may produce chronic changes inneurotransmitter concentrations, metabolism, and/or nerve changes tostimulation thresholds, for example, such that depression may bealleviated.

Non-cortical neurons (e.g., cranial nerves, peripheral nerves, sensorynerves) may be stimulated by an induced electric field. For example,peripheral nerves may be intentionally stimulated to diagnoseneuropathologies, for example, by observing response times andconduction velocities in response to a pulsed magnetic field inducedstimulus. Discomfort and/or pain may result if the induced electricfield applied to a peripheral and/or cranial nerve is very intense,and/or focused on a small area of the nerve. This discomfort may bediminished, for example, by intentionally over-stimulating the sensorynerves in the affected nerve bundle so that they can no longer respondto external pain stimuli, or by reducing the intensity and/or focus ofthe induced electric field that is causing the pain sensation.

Transcutaneous magnetic stimulation may not be limited to treatment ofdepression. Transcutaneous magnetic stimulation may be used to treat apatient, such as a human, for example, suffering from epilepsy,schizophrenia, Parkinson's disease, Tourette's syndrome, amyotrophiclateral sclerosis (ALS), multiple sclerosis (MS), Alzheimer's disease,attention deficit/hyperactivity disorder, obesity, bipolardisorder/mania, anxiety disorders (e.g., panic disorder with and withoutagoraphobia, social phobia also known as social anxiety disorder, acutestress disorder and/or generalized anxiety disorder), post-traumaticstress disorder (one of the anxiety disorders in DSM), obsessivecompulsive disorder (e.g., one of the anxiety disorders in DSM), pain(such as, for example, migraine and trigeminal neuralgia, as well aschronic pain disorders, including neuropathic pain, e.g., pain due todiabetic neuropathy, post-herpetic neuralgia, and idiopathic paindisorders, e.g., fibromyalgia, regional myofascial pain syndromes),rehabilitation following stroke (neuro plasticity induction), tinnitus,stimulation of implanted neurons to facilitate integration,substance-related disorders (e.g., dependence, abuse and withdrawaldiagnoses for alcohol, cocaine, amphetamine, caffeine, nicotine,cannabis and the like), spinal cord injury andregeneration/rehabilitation, stroke, head injury, sleep deprivationreversal, primary sleep disorders (primary insomnia, primaryhypersomnia, circadian rhythm sleep disorder), cognitive enhancements,dementias, premenstrual dysphoric disorder (PMS), drug delivery systems(changing the cell membrane permeability to a drug), induction ofprotein synthesis (induction of transcription and translation),stuttering, aphasia, dysphagia, essential tremor, autism spectrumdisorders, and/or eating disorders (such as bulimia, anorexia and bingeeating).

A device may take advantage of the above principles to induce anelectric field used in a variety of applications. For example, amagnetic device may be used for electrical stimulation of the anatomy.While the discussion herein focuses on magnetic devices that are used inconnection with magnetic stimulation of anatomical tissue, a magneticdevice may be utilized in any field of endeavor.

A ferromagnetic core may be used in connection with a magnetic device toproduce a magnetic field. For example, a ferromagnetic core may includean arc-shaped (e.g., approximately hemispherical) magnetic material. Aferromagnetic core may include a highly saturable magnetic materialhaving a magnetic saturation of at least 0.5 Tesla. A ferromagnetic coremay be shaped to optimize the magnetic field distribution in thetreatment area. For example, such a magnetic field may be for purposesof carrying out transcutaneous magnetic stimulation such as, forexample, Transcranial Magnetic Stimulation (TMS), Repetitive TMS (rTMS),Magnetic Seizure Therapy (MST), deep TMS (dTMS), controlled and/orvaried pulse shape TMS (cTMS), reduction of peripheral nerve discomfort,etc. Although examples described herein may be discussed in connectionwith TMS and rTMS, the examples described herein may be utilized inconnection with any type of magnetic stimulation, such as transcutaneousmagnetic stimulation, for example. Furthermore, the embodimentspresented herein are not limited to the use of ferromagnetic coremagnetic stimulation systems, as other core materials may be used suchas, for example, an air core.

FIG. 1 is a block diagram illustrating an example of a magneticstimulation system. A magnetic stimulation system 100 may comprise asensor 110, a controller 120, a user interface 130, a power supply 140,and a magnetic stimulation component 150. A magnetic stimulation devicemay refer to one or more components of a magnetic stimulation system(e.g., the magnetic stimulation system 100).

The magnetic stimulation component 150 may be configured to generate apulsing magnetic field 160 to conduct magnetic stimulation therapy on atreatment area of a patient. The magnetic stimulation therapy may be,for example, transcranial magnetic stimulation (TMS). TMS may refer toTMS, repetitive transcranial magnetic stimulation (rTMS), deep TMS(dTMS), cTMS, or the like. The magnetic stimulation component 150 may bea treatment coil. The magnetic stimulation component 150 may include asingle treatment coil, multiple treatment coils and/or an array oftreatment coils. The treatment area may be the prefrontal cortex, forexample. The magnetic stimulation component 150 may or may not include acore, such as a magnetic core (e.g., ferromagnetic core), for example.The pulsing magnetic field 160 may include one or more pulse bursts. Apulse burst (e.g., each pulse burst) of the pulsing magnetic field 160may include one or more pulses.

The sensor 110 may be configured to generate a signal associated with apulsing magnetic field 160. The sensor 110 may be placed between themagnetic stimulation component 150 and a treatment area of a patient.The sensor 110 may be configured to generate a signal associated withthe pulsing magnetic field 160 of the magnetic stimulation component 150(e.g., a signal induced by the pulsing magnetic field 160). For example,the sensor 110 may convert a physical property (e.g., the strength ofpulsing magnetic field 160) into a corresponding electrical signal(e.g., a current signal or a voltage signal). As such, the sensor 110may detect and/or measure a physical parameter of the pulsing magneticfield and generate a signal associated with the pulsing magnetic fieldusing the detected/measured physical parameter. The generated signal maybe a voltage signal, a current signal, and/or the like that may beproportional to a change in the pulsing magnetic field 160. For example,a current may be generated in the sensor 110 that may be proportional tothe pulsing magnetic field 160. The sensor 110 may generate a voltagethat may be proportional to the magnetic flux density (dB/dt) of thepulsing magnetic field 160.

The sensor 110 may include one or more of a conductive coil, a loop(e.g., having a number of turns based on the pulsing magnetic field), aHall sensor, a magnetoresistive material, a Faraday effect sensor, aKerr effect sensor, a flux gate sensor, an inductance change element, anerve tissue response measurement device, an electric field sensor(e.g., in a conductive field), and/or the like. The sensor 110 may beconfigured to generate more than one signal, for example, more than onesignal that is associated with the pulsing magnetic field 160 generatedby the magnetic stimulation component 150.

The controller 120 may be any type of hardware, software, or combinationthereof. The controller 120 may be configured to control one or more ofthe components of the magnetic stimulation system 100, such as thesensor 110, the user interface 130, the power supply 140, and/or themagnetic stimulation component 150, for example to conduct magneticstimulation therapy. For example, the controller 120 may include ageneral purpose processor, a special purpose processor, a conventionalprocessor, a digital signal processor (DSP), a plurality ofmicroprocessors, one or more microprocessors in association with a DSPcore, a microcontroller, any other type of integrated circuit (IC), astate machine, and/or the like.

The controller 120 may be configured to receive inputs from the userinterface 130 and/or the sensor 110 to conduct magnetic stimulationtherapy accordingly. For example, the controller 120 may perform signalcoding, data processing, power control, input/output processing, and/orany other functionality that enables the controller 120 to operate themagnetic stimulation component for magnetic stimulation. Although thecontroller 120 of the magnetic stimulation system 100 may be configuredto control both the magnetic stimulation component 150 and the sensor,the magnetic stimulation system 100 may include two or more controllersfor individually controlling two or more of the components of themagnetic stimulation system 100.

The controller 120 may be configured to estimate (e.g., measure)characteristics associated with the signal generated by the sensor 110(e.g., associated with one or more peaks of the signal). The controller120 may estimate a subset of the pulses of the signal or may estimatethe signal continuously. By estimating characteristics of the signal,the controller 120 may estimate a model of what is incurring in thebrain of a patient in response to the pulsing magnetic field.

As described herein, the controller 120 may be configured to estimate acharacteristics associated with the signal generated by the sensor 110.For example, the controller 120 may estimate a voltage associated withthe generated signal (e.g., a voltage associated with a peak of thegenerated signal), a current associated with the generated signal (e.g.,a current associated with a peak of the generated signal), a Root MeanSquare (RMS) value associated with the generated signal (e.g., a RMSvalue associated with a peak of the generated signal), a zero-cross timeassociated with the generated signal (e.g., a zero-cross time associatedwith a peak of the generated signal), a time value associated with thegenerated signal (e.g., a time value associated with a peak of thegenerated signal), and/or a time duration of the generated signal (e.g.,a time duration associated with a peak of the generated signal, forexample, peak duration). For example, the peak duration may becharacterized by a time duration between an initial rising edge of apeak and a first zero-crossing of the peak.

The controller 120 may determine one or more characteristics associatedwith the signal generated by the sensor 110. For example, the controller120 may determine characteristic(s) associated with the signal using oneor more estimated characteristics of the signal. As described herein,the controller 120 may determine a decay rate of the generated signal, afrequency of the generated signal, a timing associated with thegenerated signal, a magnetic flux associated with the generated signal,a pulse shape of the generated signal, a voltage associated with thegenerated signal, and/or a current associated with the generated signal.

The pulsing magnetic field 160 may be characterized by one or more pulsebursts. A pulse burst may be characterized by one or more pulses.Characteristics associated with the signal generated by the sensor 110may be associated with the same pulse of the pulsing magnetic field 160or different pulses of the pulsing magnetic field 160. Thecharacteristics associated with the generated signal may be associatedwith the same pulse burst of the pulsing magnetic field 160 or differentpulse bursts of the pulsing magnetic field 160.

The controller 120 may determine whether a failure has occurred based onone or more characteristics of the signal generated by the sensor 110.For example, the controller 120 may determine whether a failure hasoccurred based on whether a characteristic of the generated signal(e.g., a determined characteristic) is outside of a predeterminedacceptance window. The predetermined acceptance window may be definedbased on an expected signal associated with the pulsing magnetic field.The acceptance window may be adjustable based on the settings of thetype of magnetic stimulation therapy, the magnetic stimulation treatmentparameters, and/or the patient parameters. For example, the controller120 may receive settings of the magnetic stimulation procedure andcompare the settings of the magnetic stimulation procedure withcharacteristic(s) of the generated signal to determine whether a failurehas occurred. For example, the controller 120 may determine that afailure has occurred when a difference between two or morecharacteristics (e.g., characteristics relating to peaks) of thegenerated signal exceeds an expected value (e.g., which may bedetermined based on magnetic stimulation settings). For example, theexpected value may include an expected voltage value, an expectedcurrent value, and/or the like.

In the event a failure is determined to have occurred, the controller120 may enter a failure mode. In the failure mode, the controller 120may pause the magnetic stimulation procedure, shut down the magneticstimulation component 150, alert a user of the magnetic stimulationsystem 100, and/or alter a current applied to the magnetic stimulationcomponent 150. For example, when the controller 120 enters the failuremode, the controller 120 may adjust the frequency at which it estimatescharacteristics of the generated signal. For example, the controller 120may check for failures more frequently after a first failure isdetected.

The controller 120 may log one or more characteristics of the signalgenerated by the sensor 110 (e.g., estimated characteristics and/ordetermined characteristics). The controller 120 may be configured to logone or more failures of the magnetic stimulation procedure. In one ormore embodiments, the magnetic stimulation system 100 may include anindicator that may indicate to a user of the magnetic stimulation system100 that a failure has occurred. For example, the indicator may be alight, a speaker, an icon displayed on the user interface 130, and/orthe like.

The user interface 130 may be any type of interface in which a user ofthe magnetic stimulation system 100 may initiate, adjust, and/or end themagnetic stimulation procedure. For example, the user interface mayinclude a personal computer (PC), a keyboard, a mouse, a touchscreen, awireless device, and/or the like, that allows for an interface betweenthe user and the magnetic stimulation system 100.

The power supply 140 may be any type of power source that providessufficient energy for the magnetic stimulation component 150 to generatethe pulsing magnetic field 160 for its intended purpose, for example,for TMS, rTMS, MST or any other type of application. For example, thepower supply 140 may be a conventional 120 or 240 VAC main power source.

FIG. 2 is a block diagram illustrating an example of a magneticstimulation system. The magnetic stimulation system 200 may comprise asensor 210, a controller 220, a user interface 230, a power supply 240,a magnetic stimulation component 250, a connector cable 252, a switchand protection circuit 254, a capacitor 256, and reverse voltageprotection logic 258. The magnetic stimulation system 200 may besubstantially similar to the magnetic stimulation system 100.

The sensor 210 may be substantially similar to the sensor 110 describedherein. The sensor 210 may be configured to perform one or more of thefunctions described herein with reference to the sensor 110. Forexample, the sensor 210 may be configured to generate a signalassociated with a pulsing magnetic field 260.

The magnetic stimulation component 250 may be substantially similar tothe magnetic stimulation component 150 described herein. The magneticstimulation component 250 may be configured to perform one or more ofthe functions described herein with reference to the magneticstimulation component 150. For example, the magnetic stimulationcomponent 250 may generate a pulsing magnetic field 260 that may be usedto conduct magnetic stimulation therapy on a treatment area of apatient.

The user interface 230 may be substantially similar to the userinterface 130 described herein. For example, the user interface 230 maybe configured to perform one or more of the functions described hereinwith reference to the user interface 130. The power supply 240 may besubstantially similar to the power supply 140 described herein. Forexample, the power supply 240 may be configured to perform one or moreof the functions described herein with reference to the power supply140.

The controller 220 may include signal conditioning logic 222, signalacquisition logic 224, analysis comparison logic 226, triggering logic229, and timing control logic 228. The controller 220 may besubstantially similar to the controller 120 described herein. Forexample, the controller 220 may be configured to perform one or more ofthe functions described herein with reference to controller 120. Thecontroller 220 may be any type of hardware, software, and/or combinationthereof. The controller 220 may be configured to control one or more ofthe components of the magnetic stimulation system 200. For example, thecontroller 220 may be configured to estimate and/or determine one ormore characteristics associated with the generated signal, and/or thecontroller 220 may be configured to determine whether a failure hasoccurred based on a characteristic of the signal generated by the sensor210.

The controller 220, for example, via the signal conditioning logic 222,may receive a signal from the sensor 210. The signal conditioning logic222 may manipulate the signal received from the sensor 210 into a formatused by the controller 220 for further processing. For example, thesignal conditioning logic 222 may filter, amplify, and/or isolate thesignal received from the sensor 210. The signal received from the sensor210 may include a voltage signal, a current signal, or the like that isproportional to the pulsing magnetic field 260.

The signal acquisition logic 224 may receive the generated signal fromthe signal conditioning logic 222. The signal acquisition logic 224 maysample the signal and/or convert the signal into a digital signal thatmay be utilized by the controller 220. The signal acquisition logic 224may include one or more analog-to-digital converters. For example, thesignal acquisition logic 224 may receive an analog signal from thesignal conditioning logic 222 and may convert the signal into a digitalsignal for further processing by the controller 220.

The analysis comparison logic 226 may receive the signal from the signalacquisition logic 224. The analysis comparison logic 226 may compare acharacteristic of the signal with a setting of the magnetic stimulationsystem to determine whether a failure has occurred. For example, thesetting of the magnetic stimulation system may include one or moreexpected characteristics of the pulsing magnetic field 260 generated bythe magnetic stimulation component 250. The characteristics of thepulsing magnetic field 260 may be specific to the treatment beingconducted by the magnetic stimulation system. As such, the analysiscomparison logic 226 may analyze whether the magnetic stimulation system(e.g., the magnetic stimulation component 250) is properly providingtreatment.

The timing control logic 228 may coordinate the timing of the componentsof the magnetic stimulation system 200. For example, the timing controllogic 228 may coordinate the timing between the magnetic stimulationcomponent 250 and the signal generated by the sensor 210 (e.g., andreceived via the controller 220). As such, the timing control logic 228may ensure that the controller 220 is comparing a signal generated bythe sensor 210 with a corresponding pulsing magnetic field 260 generatedby the magnetic stimulation component 250.

The triggering logic 229 may initiate actions of the magneticstimulation system 200 when certain events occur. The triggering logic229 may receive timing information from the timing control logic 228.The triggering logic 229 may determine the timing relationship between asignal generated by the sensor 210 and the pulsing magnetic field 260.For example, the triggering logic 229 may determine whether or not asignal received from the sensor 210 is in response to the pulsingmagnetic field 260. The triggering logic 229 may relay this informationto the analysis comparison logic 226 so the occurrence of a failure maybe determined.

The controller 220 may include more or less than the componentsillustrated in FIG. 2. For example, the controller 220 may include anedge detection circuit. The edge detection circuit may be configured tomeasure a start time and an end time of a pulse of the generated signalindicative of the pulsing magnetic field. The controller 220 may includea peak detection circuit. The peak detection circuit may be configuredto receive the generated signal (e.g., from the sensor 210) anddetermine one or more peaks of a pulse(s) of the generated signal. Forexample, the peak detection circuit may be configured to determine oneor more characteristics (e.g., voltage, current, time, etc.) associatedwith a peak of a pulse(s) of the generated signal.

The connector cable 252 may provide for an electrical connection and/orelectrical communication between the magnetic stimulation component 250and the switch and protection circuit 254. The switch and protectioncircuit 254 may be any type of electrical switching device that canoperate the magnetic stimulation system (e.g., the magnetic stimulationcomponent 250), for example, by switching power from the capacitor 256and/or the power supply 240 on and off. For example, the switch andprotection circuit 254 may be operated to switch power from the powersupply 240 to charge the capacitor 256. The switch and protectioncircuit 254 may be used to discharge the capacitor 256 through themagnetic stimulation component 250, for example, to generate the pulsingmagnetic field 260 that may be used for treatment. As such, when theswitch and protection circuit 254 activates to produce the pulse in themagnetic stimulation component 250, currents (e.g., peak currents inexcess of 1000 A) may be delivered to the magnetic stimulation component250 from the charge stored on the capacitor 256.

The capacitor 256 may provide energy storage for the magneticstimulation component 250. The capacitor 256 may include a singlecapacitor and/or a capacitor bank. The capacitor 256 may include anynumber and/or type of capacitor(s) that are appropriate for the powerlevel, charging time, and/or pulse type used by the magnetic stimulationsystem 200. For example, the capacitor 256 may include eight 10 μFcapacitors that may be connected in parallel to result in 80 μF of totalcapacitance. For example, the capacitor 256 may be a single 80 μFcapacitor.

The capacitor 256 may be used, for example, in applications where a 120VAC power source or the like is available (e.g., where only a 120 VACpower source or the like is available). A typical doctor's office may beequipped with a conventional (e.g., 120 VAC or the like) power supplyrather than a higher-power 240 VAC or three-phase power supply. Thecapacitor 256 may be used to produce higher peak currents in themagnetic stimulation component 250 than would be possible by driving themagnetic stimulation component 250 directly from the power supply 240alone. For example, the power supply 240 may convert 120 VAC at itsinput to 1500 VDC at its output, with the DC output capable of producing1 Amp DC at 1500 VDC. Using capacitor 256 may allow for higher peakpulse current to flow into the magnetic stimulation component 250 thanthe 1 Amp produced by the power supply 240. As such, the capacitor 256may be charged up to the power supply's 240 output voltage in the timeperiod between pulses that are delivered to the magnetic stimulationcomponent 250. When the switch and protection circuit 254 activates toproduce the pulse in the magnetic stimulation component 250, peakcurrents in excess of 1000 A may be delivered to the magneticstimulation component 250 from the charge stored on the capacitor 256.The magnitude of this peak current may be dictated by the inductance ofthe magnetic stimulation component 250, and/or by the capacitance valueand/or voltage level stored on the capacitor 256 prior to the pulse. Thecapacitor 256 may be used regardless of the type of power supply 240available. For example, the capacitor 256 may be used in situationswhere the power supply 240 is a 240 VAC or three-phase power supply to,for example, produce desired peak currents for input into the magneticstimulation component 250.

The reverse voltage protection 258 may include reverse bias protectionfor the magnetic stimulation system 200 (e.g., for the magneticstimulation component). For example, the reverse voltage protection 258may include one or more diodes (e.g., blocking diode, Schottky diode,etc.) and/or a receiver bias protection switch (e.g., PNP transistor,P-Channel FET, etc.).

FIG. 3 is a diagram illustrating an example waveform of a signalreceived by a magnetic stimulation system (e.g., magnetic stimulationsystem 100 or magnetic stimulation system 200). As described herein, acontroller (e.g., controller 120 or controller 220) may receive a signalfrom a sensor (e.g., sensor 110 or sensor 210) that may be indicative ofa pulsing magnetic field (e.g., pulsing magnetic field 160 or pulsingmagnetic field 260) generated by a magnetic stimulation component (e.g.,magnetic stimulation component 150 or magnetic stimulation component250). For example, a current may be generated in the sensor that may beproportional to the pulsing magnetic field. The sensor may generate avoltage that may be proportional to a rate of change of the magneticflux density (dB/dt) of the pulsing magnetic field. The signal receivedby the controller may include a voltage signal, such as voltage signal300. Although described with reference to voltage signal 300, the signalreceived by the controller from the sensor may be in other units (e.g.,a current signal, a power signal, and/or the like).

The magnetic stimulation system may be configured to estimate one ormore characteristics associated with the signal generated by the sensor(e.g., generated signal 300), for example, as described herein. Themagnetic stimulation system may be configured to determine one or morecharacteristics associated with the generated signal based on theestimated characteristic(s), for example, as described herein. Theestimated and/or determined characteristics of the generated signal mayinclude a pulse repetition rate, pulse interval, stimulation interval,timing of a zero-crossing, a timing of a peak of a pulse, amplitude of apeak, pulse shape, peak to RMS ratio, pulse duration, peak duration,rolling average of one or more pulses, and/or the like, for example, asdescribed herein with reference to voltage signal 300.

The voltage signal 300 may include one or more pulses and one or morepulse bursts. A pulse of the voltage signal may correspond with a pulseof the pulsing magnetic field. A pulse burst may include one or morepulses. The voltage signal 300 may include a first pulse 301, a secondpulse 302, a third pulse 303, a fourth pulse 304, and a fifth pulse 305.The first pulse 301, the second pulse 302, and the third pulse 303 maybe part of a first pulse burst. The fourth pulse 304 and the fifth pulse305 may be part of a second pulse burst.

A pulse may include an initial rising edge, a first peak, a second peak,a third peak, and a pulse interval. For example, the first pulse 301 mayinclude an initial rising edge 310, a first peak 312, a second peak 314,a third peak 316, and a pulse interval 320. The initial rising edge of apulse may be a time when the pulse begins, for example, when the pulseexceeds 0 V. The first peak of the pulse may be characterized by a timeand a maximum voltage of the pulse after the initial rising edge andbefore the pulse decreases back to 0 V. The second peak of the pulse maybe characterized by a time and a minimum voltage of the pulse after azero-crossing after the first peak and before the pulse increases backto 0 V. The third peak of the pulse may be characterized by a time and asecond maximum voltage after a zero-crossing after the second peak andbefore the pulse decreases back to 0 V. After the third peak, the pulsemay decrease to 0 V (e.g., after crossing 0 V one or more times, forexample, oscillating) and before an initial rising edge of a subsequentpulse.

The pulse interval may be indicative of a time between an initial risingedge of a pulse to an initial rising edge of a subsequent pulse. Forexample, the pulse interval 320 may be indicative of the time betweenthe initial rising edge 310 of the first pulse 301 to the initial risingedge of the second pulse 302. The stimulation time of a pulse burst maybe calculated based on the time between the initial rising edge of afirst pulse in the pulse burst to the initial rising edge of the lastpulse in the pulse burst. For example, stimulation time 330 may indicatethe time duration between the initial rising edge 310 of the first pulse301 to the initial rising edge of the third pulse 303. For example, thestimulation time 330 may be indicative of the duration of time of apulse burst of the pulsing magnetic field. The stimulation interval maybe indicative of a time between the initial rising edge (e.g., the firstpeak) of a last pulse in a pulse burst to the initial rising edge (e.g.,the first peak) of a first pulse in a subsequent pulse burst. Forexample, the stimulation interval 340 may be indicative of the timebetween pulse bursts of a pulsing magnetic field. For example, thestimulation interval 340 may indicate the time between the initialrising edge (e.g., the first peak) of the third pulse 303 (e.g., whichmay be the last pulse of the first pulse burst) to the initial risingedge (e.g., the first peak) of the fourth pulse 304 (e.g., which may bethe first pulse of the second pulse burst).

FIG. 4A is a flow diagram illustrating an example procedure fordetermining whether a failure has occurred. The procedure 400 may beperformed (e.g., partially or entirely) by a magnetic stimulationsystem, for example, the magnetic stimulation system 100 or the magneticstimulation system 200, as described herein. For example, the entiretyor a subset of the operations described with reference to the procedure400 may be performed by one or more of the magnetic stimulation systemsas described herein. The procedure 400 may be performed before treatment(e.g., for calibration of the magnetic stimulation system), duringtreatment, and/or after treatment. As such, the procedure 400 may beperformed without a patient present.

At 402, a magnetic stimulation system (e.g., a magnetic stimulationcomponent) may generate a pulsing magnetic field. The pulsing magneticfield may be generated for magnetic stimulation treatment, forpreparation of magnetic stimulation treatment, to calibrate the system,and/or the like. The pulsing magnetic field may include one or morepulse bursts. A pulse burst may include one or more pulses. The pulsebursts may vary from one another. For example, the pulse bursts may beat different voltage levels, have a different number of pulses per pulseburst, and/or have a different stimulation time. For example, thepulsing magnetic field may pulse approximately 0.1 to 100 pulses persecond (pps) (Hz). This may be referred to as the pulse repetition rate.For example, the frequency of a pulse may be approximately 1-10 kHz. Forexample, the pulsing magnetic field may include approximately ten pulsesper second for four seconds, followed by a brief intermission (e.g.,which may be repeated). In total, the pulsing magnetic field may includeapproximately 3,000 pulses over a 37 minute period. The stimulationvoltage (e.g., which may refer to the maximum voltage of a pulse) may beapproximately 1 V.

At 404, a sensor of the magnetic stimulation system may generate asignal associated with the pulsing magnetic field, for example, asdescribed herein. The generated signal may include one or more peaks. At406, the magnetic stimulation system (e.g., a controller) may estimateone or more characteristics associated with the generated signal, forexample, as described herein. The generated signal may include a voltagesignal, for example, that may be proportional to a change in the pulsingmagnetic field generated by the magnetic stimulation system. Thegenerated signal may include a current signal, for example, that may beproportional to a change in the pulsing magnetic field generated by themagnetic stimulation system.

The magnetic stimulation system may estimate a characteristic associatedwith a peak of the generated signal. The generated signal may includeone or more pulses, each of which may include one or more peaks. Thepeak of a generated signal may be any of the peaks described herein, forexample, the first peak of a pulse, the second peak of a pulse, or thethird peak of a pulse. The first peak of a generated signal (e.g., orsecond peak, or third peak) may or may not correspond to the first peakof a pulse (e.g., or second peak, or third peak, respectively) of thegenerated signal. For example, the first peak of a generated signal mayrefer to the first, second, or third peak of a pulse of the generatedsignal.

Estimating a characteristic associated with a peak of the generatedsignal may include measuring the characteristic associated with the peakof the generated signal. The characteristic associated with the peak ofthe generated signal may include a voltage of the peak, a current of thepeak, a root mean square (RMS) value of the peak, a zero-cross of thepeak (e.g., a time associated with a zero-cross of a peak), a time valueof the peak, a time duration of the peak, and/or the like. Thezero-cross of a peak may refer to a time associated with the zero-crossimmediately preceding the peak and/or the zero-cross following to thepeak.

The magnetic stimulation system may estimate one or more characteristicsassociated with one or more peaks of the generated signal. The peak(s)of the generated signal may be associated with a single pulse of thepulsing magnetic field generated by the magnetic stimulation system. Thepeak(s) of the generated signal may be associated with more than onepulse of the pulsing magnetic field. For example, the peak(s) of thegenerated signal may be associated with one or more pulse bursts of thepulsing magnetic field. The magnetic stimulation system may estimatecharacteristic(s) of more than one peak of more than one pulse of thepulsing magnetic field.

At 408, it may be determined whether a failure has occurred, forexample, as described herein. The magnetic stimulation system mayestimate characteristic(s) of the generated signal (e.g., at 406). Themagnetic stimulation system may determine characteristic(s) of thegenerated signal based on the estimated characteristic(s) of thegenerated signal. For example, a determined characteristic of thegenerated signal may include a decay rate of the generated signal, afrequency of the generated signal, a timing associated with thegenerated signal, a magnetic flux associated with the generated signal,a current associated with the generated signal, a voltage associatedwith the generated signal, and/or a combination thereof.

The magnetic stimulation system may determine whether a failure hasoccurred based on the determined characteristic(s) of the generatedsignal. For example, the magnetic stimulation system may determinewhether a failure has occurred based on whether a characteristic of thegenerated signal (e.g., a determined characteristic) is outside of apredetermined acceptance window. The predetermined acceptance window maybe set based on an expected signal associated with the pulsing magneticfield. For example, the magnetic stimulation system may be configuredwith, preconfigured with, and/or configured to receive one or moresettings of the magnetic stimulation procedure and compare thesetting(s) with one or more characteristics of the generated signal todetermine whether a failure has occurred. The magnetic stimulationsystem may determine that a failure has occurred when a differencebetween two or more characteristics (e.g., characteristics relating topeaks) of the generated signal exceeds an expected value (e.g., whichmay be determined based on magnetic stimulation settings). For example,the expected value may be an expected voltage value or an expectedcurrent value.

If a failure is determined to have occurred at 408, then the magneticstimulation system may enter failure mode at 410. In failure mode, themagnetic stimulation system may pause the magnetic stimulationprocedure, shut down the magnetic stimulation system, alert a user ofthe magnetic stimulation system that a failure has occurred, and/oralter a current applied to the magnetic stimulation component. When themagnetic stimulation system enters the failure mode, the magneticstimulation system may adjust the frequency at which it estimatescharacteristics of the generated signal. For example, the magneticstimulation system may check for failures more frequently after afailure is detected. If a failure is determined not to have occurred at408, then the magnetic stimulation system may continue generating thepulsing magnetic field (e.g., until a magnetic stimulation treatmentsession is complete, until calibration is complete, and/or the like).

FIG. 4B is a flow diagram illustrating an example procedure fordetermining whether a failure has occurred. The procedure 450 may beperformed (e.g., partially or entirely) by a magnetic stimulationsystem, for example, the magnetic stimulation system 100 or the magneticstimulation system 200, as described herein. For example, the entiretyor a subset of the operations described with reference to procedure 450may be performed by one or more of the magnetic stimulation systems asdescribed herein. The procedure 450 may be performed before treatment(e.g., for calibration of the magnetic stimulation system), duringtreatment, and/or after treatment. As such, the procedure 450 may beperformed without a patient present.

The procedure 450 may begin at 452 when the magnetic stimulation systemis started. At 454, the patient parameters may be set-up. The patientparameters may include one or more parameters relating to the patient.For example, the patient parameters may include physical characteristicsof the patient, such as height, weight, age, gender, and/or the like, anumber of previous treatments the patient has received, a number oftreatments the patient is currently receiving, etc. The patient does nothave to be present for the procedure 450 to be performed.

At 456, the pulse sequence may be set-up. The pulse sequence parametersmay include one or more parameters relating to the magnetic stimulationprocedure, such as a duration for the magnetic stimulation procedure, astrength(s) for the magnetic stimulation procedure, a number of pulsesand/or pulse bursts of the magnetic stimulation procedure, parameter(s)relating to the pulses and/or pulse bursts of the magnetic stimulationprocedure, and/or the like. At 458, the power supply of the magneticstimulation component may be turned on. This may initialize the magneticstimulation system for the generation of a pulsing magnetic field.

At 460, one or more test pulses may be generated by the magneticstimulation system (e.g., the magnetic stimulation component). The testpulses may be utilized to determine whether or not the magneticstimulation system is working properly before initiating the treatmentfor the patient. As such, the test pulses may be performed without themagnetic stimulation component and/or the patient in position fortreatment. For example, the test pulses may include a total of sevenpulses; three pulses at two different voltage levels followed by aclearing pulse. At 462, it may be determined whether a failure hasoccurred. The determination may be performed by the magnetic stimulationsystem, for example, as described herein. If a failure is determined tohave occurred, then the magnetic stimulation system may enter failuremode at 464. The failure mode may be as described herein.

If a failure is determined not to have occurred, then the test pulseresults may be analyzed at 466. The test pulse results may be analyzedto properly configure the magnetic stimulation treatment for thepatient. For example, even if a failure is determined not to haveoccurred at 462, the test pulses may be used to more accuratelycalibrate the magnetic stimulation treatment for the patient.

After 466, the procedure 450 may include one or more of the processesdescribed with reference to procedure 400. The procedure 450 may be aprecursor to magnetic stimulation therapy, and as such, after 466magnetic stimulation treatment may begin on a patient (e.g., the patientwhose parameters were used in 454), for example, according to procedure400.

FIGS. 5-8 are diagrams illustrating examples signals induced on a sensorof a magnetic stimulation system. As described herein, a magneticstimulation system (e.g., magnetic stimulation system 100 or magneticstimulation system 200) may be configured to determine whether a failurehas occurred during a magnetic stimulation treatment or test session.The magnetic stimulation system may be configured to determine a widevariety of different failure types. Example signals associated with suchfailures may be provided herein, for example, with reference to FIGS.6-8. The failures illustrated in FIGS. 6-8 are examples of the varioustypes of signals that may be indicative of failures that may be detectedby a magnetic stimulation system according to the one or more of theembodiments described herein. Further, the specific values associatedwith the signals of FIGS. 5-8 are examples and may be altered based onthe specific magnetic stimulation treatment procedure being conducted,for example, in accordance with the settings of the magnetic stimulationprocedure. The failure determinations described herein may be performedby a magnetic stimulation system (e.g., the magnetic stimulation system100 or the magnetic stimulation system 200).

FIG. 5 is a diagram illustrating an example signal of an expectedvoltage generated by (e.g., induced on) a sensor. Although one pulse isillustrated in FIG. 5, the signal 500 may include one or more pulses ofone or more pulse bursts. The signal 500 may be generated by a magneticstimulation system (e.g., the magnetic stimulation system 100 or themagnetic stimulation system 200), for example, by a sensor of themagnetic stimulation system. The signal 500 may be provided to acontroller of a magnetic stimulation system, for example, to determinewhether a failure has occurred. The pulse of the signal 500 may includean initial rising edge 510, a first peak 502, a first zero-crossing 512,a second peak 504, a second zero-crossing 514, a third peak 506, and athird zero-crossing 516, for example, as described herein.

The signal 500 may be an expected voltage that is induced on the sensor.The magnetic stimulation system may utilize the signal 500 to determinewhether a failure has occurred, for example, as described herein.

The signal 500 may include a pulse that is approximately 200 μs inlength. The initial rising edge 510 may be at approximately time 0. Thefirst peak 502 may be approximately 1 V and may occur approximately 5 μsafter the initial rising edge 510. The first zero-crossing 512 may occurapproximately 50 μs after the initial rising edge 510 about 45 μs afterthe first peak 502. The second peak 504 may be approximately −0.75 V andmay occur approximately 80 μs after the initial rising edge 510 andapproximately 30 μs after the first zero-crossing 512. The secondzero-crossing 514 may occur approximately 130 μs after the initialrising edge 510 about 50 is after the second peak 504. The third peak506 may be approximately 0.6 V and may occur approximately 180 μs afterthe initial rising edge 510 and approximately 50 μs after the secondzero-crossing 514. The third zero-crossing 516 may occur approximately185 μs after the initial rising edge 510 about 5 μs after the third peak506. The signal 500 may attenuate until settling at 0 V approximately200 μs after the initial rising edge 510. As described herein, thesignal 500 may include one or more pulses of one or more pulse bursts. Apulse of the signal 500 may look substantially similar to the pulseillustrated in FIG. 5.

FIG. 6 is a diagram illustrating an example signal of a voltagegenerated by (e.g., induced on) a sensor that is indicative of afailure. Although one pulse is illustrated in FIG. 6, the signal 600 mayinclude one or more pulses of one or more pulse bursts. As shown, thepulse of the signal 600 may include an initial rising edge 610, a firstpeak 602, a first zero-crossing 612, a second peak 604, a secondzero-crossing 614, a third peak 606, and a third zero-crossing 616, forexample, as described herein. The first zero-crossing 612 may bereferred to as a characteristic associated with the first peak 602, thesecond zero-crossing 614 may be referred to as a characteristicassociated with the second peak 604, and/or the third zero-crossing 616may be referred to as a characteristic associated with the third peak606. An acceptance window may be adjustable based on the settings of thetype of magnetic stimulation therapy, the magnetic stimulation treatmentparameters, and/or the patient parameters. Failure detection may beperformed during a test session, before magnetic stimulation therapy,and/or after magnetic stimulation therapy.

The magnetic stimulation system may detect a failure during a magneticstimulation treatment session based on the decay rate of the pulsingmagnetic field. For example, decay rate may refer to a rate at which apulse associated with a pulsing magnetic field diminishes from the firstpeak to the last peak. Referring to FIG. 6, the signal 600 may becharacterized by excessive loss. Excessive loss may be indicative ofincreased resistance of the magnetic stimulation system, which, forexample, may be due to the failure of a connector and/or a switch of themagnetic stimulation system. The magnetic stimulation system maydetermine that a failure has occurred if the voltage ratio of the signal600 is outside of a predetermined threshold, for example, a decay ratioacceptance window. The voltage ratio of the signal 600 may be the ratiobetween a voltage associated with two or more peaks of the signal 600,for example, a voltage associated with the first peak 602 and a voltageassociated with the second peak 604.

For example, the magnetic stimulation system may determine that afailure has occurred if a voltage ratio of a generated signal (e.g.,signal 600) is outside of a predetermined threshold. The magneticstimulation system may estimate the voltage associated with two or morepeaks of the generated signal (e.g., the first peak 602 and the secondpeak 604 of the pulse of the generated signal 600). The magneticstimulation system may determine the voltage ratio of the generatedsignal using the voltage associated with the two or more peaks of thegenerated signal. For example, the voltage ratio may be a ratio of thevoltage of a second peak (e.g., the second peak 604) to the voltage of afirst peak (e.g., the first peak 602).

The magnetic stimulation system may determine if a failure has occurredusing the voltage ratio, for example, by checking if the voltage ratiois outside of the decay ratio acceptance window. The decay ratioacceptance window may vary depending on one or more settings of themagnetic stimulation procedure. For example, the decay ratio acceptancewindow may be a range of the voltage ratio of the signal between avoltage value of a second peak (e.g., the second peak 604) and a voltagevalue of a first peak (e.g., the first peak 602). The decay ratioacceptance window may be a percentage (e.g., 10%), meaning that thevoltage ratio of the signal may be plus/minus the percentage of theexpected voltage ratio (e.g., as determined in accordance with theexpected signal 500) to be within the decay ratio acceptance window. Ifthe voltage is outside of the decay ratio acceptance window, then afailure may be determined to have occurred. For example, the decay ratioacceptance window may be between 0.6-1.0. For example, the decay ratioacceptance window may be between 0.65-0.95. For example, the decay ratioacceptance window may be between 0.65-0.85.

The magnetic stimulation system may determine that a failure hasoccurred if a voltage difference of two of the peaks of a signal (e.g.,signal 600) generated by a sensor is outside of a predeterminedthreshold. The voltage difference may use the actual voltage values ofthe peaks or an absolute voltage value of the peaks. The voltagedifference of the signal may be the voltage difference between a firstpeak and a second peak of the pulse of the generated signal (e.g., thefirst peak 602 and the second peak 604 of the signal 600). For example,the magnetic stimulation system may estimate the voltage associated withtwo or more peaks of the signal (e.g., the first peak and the secondpeak). The magnetic stimulation system may determine the voltagedifference using the voltage associated with the two or more peaks(e.g., the voltage associated with the first peak and the voltageassociated with the second peak).

The magnetic stimulation system may determine if a failure has occurredusing the voltage difference, for example, by checking if the voltagedifference is outside of the peak-to-peak acceptance window. Forexample, the peak-to-peak acceptance window may be 10%, meaning that thevoltage difference of the signal may be plus/minus 10% of the expectedvoltage difference (e.g., as determined in accordance with the expectedsignal 500) to be within the peak-to-peak acceptance window. Forexample, the peak-to-peak acceptance window may be between 1.3-2.2 V ifabsolute values of the voltage peaks are used. For example, thepeak-to-peak acceptance window may be between 1.45-2.5 V if absolutevalues of the voltage peaks are used. For example, the peak-to-peakacceptance window may be between 1.6-1.9 V, if absolute values of thevoltage peaks are used. Further, the peak-to-peak acceptance window maybe dependent upon the size of the sensor, for example, if the sensor isa pickup loop.

FIG. 7 is a diagram illustrating another example waveform of a voltagegenerated by (e.g., induced on) a sensor during a magnetic stimulationtreatment that is indicative of a failure. Although one pulse isillustrated in FIG. 7, the signal 700 may include one or more pulses ofone or more pulse bursts. As shown, the pulse of the signal 700 mayinclude an initial rising edge 710, a first peak 702, a firstzero-crossing 712, a second peak 704, a second zero-crossing 714, athird peak 706, and a third zero-crossing 716, for example, as describedherein. The first zero-crossing 712 may be referred to as acharacteristic associated with the first peak 702, the secondzero-crossing 714 may be referred to as a characteristic associated withthe second peak 704, and/or the third zero-crossing 716 may be referredto as a characteristic associated with the third peak 706. An acceptancewindow may be adjustable based on the settings of the type of magneticstimulation therapy, the magnetic stimulation treatment parameters,and/or the patient parameters. Failure detection may be performed duringa test session, before magnetic stimulation therapy, and/or aftermagnetic stimulation therapy.

The magnetic stimulation system may detect a failure based on theamplitude of a peak of the pulsing magnetic field. For example, theamplitude of a peak may refer to the maximum or minimum voltage and/orcurrent associated with the peak. The signal 700 may be characterized bysmaller peak voltages. Smaller peak voltages, for example, asillustrated by signal 700, may be indicative of a failure that reducesthe capacitor charge and/or the voltage applied to the magneticstimulation component by the magnetic stimulation system. For example, asignal 700 may be received if a power supply, connector, thyrister,shunt device, wiring, and/or the like of the magnetic stimulation systemhad failed or begun to fail. The magnetic stimulation system maydetermine that a failure has occurred if an amplitude (e.g., voltage orcurrent) associated with a peak of the signal 700 is outside of apredetermined threshold, for example, an amplitude acceptance window.For example, the amplitude of a peak of the signal 700 may refer to thevoltage at the first peak 702, the second peak 704, and/or the thirdpeak 706.

The magnetic stimulation system may determine that a failure hasoccurred if an amplitude of a voltage associated with a peak of agenerated signal (e.g., signal 700) is outside of a predeterminedthreshold. The magnetic stimulation system may estimate an initialrising edge (e.g., an initial rising edge 710) and/or a zero-crossing(e.g., zero-crossing 712, 714, 716) associated with one or more peaks ofthe generated signal (e.g., the first peak 702, the second peak 704,and/or the third peak 706 of the pulse of the generated signal). Forexample, the magnetic stimulation system may determine a voltageassociated with the first peak, a voltage associated with the secondpeak, and/or a voltage associated with the third peak of the generatedsignal using the initial rising edge and/or the zero-crossing associatedwith the one or more peaks of the generated signal.

For example, the magnetic stimulation system may determine if a failurehas occurred using the amplitude of one or more peaks of the signal, forexample, by checking if the amplitude is outside of the amplitudeacceptance window. For example, the amplitude acceptance window may be10%, meaning that the amplitude of a peak of the signal may beplus/minus 10% of the expected amplitude of a peak (e.g., as determinedin accordance with the expected signal 500) to be within the amplitudeacceptance window. For example, the amplitude acceptance window may bebetween 0.7-1.3 V for a first peak of a pulse of a generated signal. Forexample, the amplitude acceptance window may be between 0.8-1.2 V for afirst peak of a pulse of a generated signal. For example, the amplitudeacceptance window may be between 0.9-1.1 V for a first peak of a pulseof a generated signal.

The magnetic stimulation system may determine that a failure hasoccurred if an average amplitude of two or more peaks (e.g., first peak702, second peak 704, and/or third peak 706) of a pulse(s) of agenerated signal (e.g., signal 700) is outside of a predeterminedthreshold. The magnetic stimulation system may estimate a voltageassociated with two or more peaks of a pulse(s) of the generated signal.The magnetic stimulation system may determine an average voltageamplitude of two or more peaks of the generated signal using the voltageassociated with the two or more peaks of the generated signal.

For example, the magnetic stimulation system may determine if a failurehas occurred using the average voltage amplitude, for example, bychecking if the average voltage amplitude is outside of an averageamplitude acceptance window. For example, the average amplitudeacceptance window may be 10%, meaning that the average amplitude of twoor more peaks of a pulse(s) of the signal may be plus/minus 10% of theexpected average amplitude (e.g., as determined in accordance with theexpected signal 500) to be within the average amplitude acceptancewindow. For example, the average amplitude acceptance window may bebetween 1.25-1.95 V for a first peak and a third peak of a pulse of agenerated signal. For example, the average amplitude acceptance windowmay be between 1.4-1.8 V for a first peak and a third peak of a pulse ofa generated signal. For example, the average amplitude acceptance windowmay be between 1.5-1.7 V for a first peak and a third of a pulse of agenerated signal.

The magnetic stimulation system may detect a failure based on the pulseshape and/or the peak to RMS voltage ratio of the pulsing magneticfield. The signal 700 may be characterized by a smaller peak to RMSratio. For example, peak to RMS ratio may be the ratio of a peak voltage(e.g., the voltage associated with the first peak 702) to the RMS valueof a peak of the signal 700. Smaller peak to RMS ratio value, forexample, as illustrated by signal 700, may be indicative of a failurethat reduces the capacitor charge and/or the voltage applied to themagnetic stimulation component by the magnetic stimulation system.

The magnetic stimulation system may determine that a failure hasoccurred if a ratio between a peak (e.g., the first peak) of a pulse ofa generated signal (e.g., signal 700) and a peak to RMS voltage ratio isoutside of a predetermined threshold. The magnetic stimulation systemmay estimate a voltage and/or a time associated with one or more peaksof a pulse(s) of the generated signal. The magnetic stimulation systemmay determine a peak to RMS voltage ratio of the generated signal usingthe voltage and/or time associated with the one or more peaks of apulse(s) of the generated signal.

For example, the magnetic stimulation system may determine if a failurehas occurred using the peak to RMS voltage ratio, for example, bychecking if the ratio between the voltage of the peak and the peak toRMS voltage ratio is outside of the peak to RMS voltage acceptancewindow. For example, the peak to RMS voltage acceptance window may be10%, meaning that the ratio between the voltage of the peak and the peakto RMS voltage ratio may be plus/minus 10% of what is expected (e.g., asdetermined in accordance with the expected signal 500) to be within thepeak to RMS voltage acceptance window. For example, the peak to RMSvoltage acceptance window may be between 1.15-1.65. For example, thepeak to RMS voltage acceptance window may be between 1.25-1.55. Forexample, the peak to RMS voltage acceptance window may be between1.3-1.5.

Pulse shape may refer to the shape of a pulse of the pulsing magneticfield. The peak to RMS ratio is one example of how a shape of thegenerated signal may be used by a magnetic stimulation system todetermine whether a failure has occurred. Other examples may be providedherein. For example, characteristics of a generated signal, such asduration, skewness, kurtosis, among others, may relate to the shape ofthe generated signal and may be used to determine whether a failure hasoccurred. The magnetic stimulation system may determine that a failurehas occurred if a shape of a generated signal is outside of apredetermined acceptance window. The magnetic stimulation system may beconfigured to estimate a pulse shape, a pulse time, a pulse amplitude,and/or a pulse duration associated with one or more peaks of a pulse(s)of a generated signal. The magnetic stimulation system may be configuredto determine one or more characteristics based on the one or moreestimated characteristics of the generated signal. The magneticstimulation system may determine that a failure has occurred when theone or more determined characteristics are outside of a predeterminedacceptance window, for example, a pulse shape acceptance window.

Skewness of the generated signal, for example, may be used determine ifa failure has occurred. The magnetic stimulation system may estimate thevoltage and/or time of one or more peaks of a pulse(s) of the generatedsignal, the magnetic stimulation system may determine the voltage pertime of the generated signal (e.g., which may be indicative of theskewness of a pulse of the generated signal), and the magneticstimulation system may determine if a failure has occurred bydetermining if the voltage per time of the generated signal falls withina skewness acceptance window.

FIG. 8 is a diagram illustrating an example waveform of a voltagegenerated by (e.g., induced on) a sensor during magnetic stimulationthat is indicative of a failure. Although one pulse is illustrated inFIG. 8, the signal 800 may include one or more pulses of one or morepulse bursts. As shown, the pulse of the signal 800 may include aninitial rising edge 810, a first peak 802, a first zero-crossing 812, asecond peak 804, a second zero-crossing 814, a third peak 806, and athird zero-crossing 816, for example, as described herein. An acceptancewindow may be adjustable based on the settings of the type of magneticstimulation therapy, the magnetic stimulation treatment parameters,and/or the patient parameters. Failure detection may be performed duringa test session, before magnetic stimulation therapy, and/or aftermagnetic stimulation therapy.

The magnetic stimulation system may detect a failure based on the pulseduration of the pulsing magnetic field. The time duration between theinitial rising edge 810 and the third zero-crossing 816 of the signal800 may be referred to as the pulse duration of the signal 800. Thesignal 800 may be characterized by a shorter pulse duration than theexpected signal 500. A shorter pulse duration, for example, asillustrated by signal 800, may be indicative of a failing capacitor, ashorted winding (e.g., in the core), a broken core, and/or the like.

The magnetic stimulation system may determine whether a failure hasoccurred based on the pulse duration of a generated signal. For example,the pulse duration may refer to the time duration between the initialrising edge of a pulse and the third zero-cross of the pulse. Forexample, the pulse duration may refer to the time duration between theinitial rising edge of a pulse and the third peak of the pulse. Forexample, the pulse duration may refer to the time duration between thefirst peak of a pulse and the third peak of a pulse. For example, thepulse duration may refer to the time duration between the firstzero-crossing and the second zero-crossing. For example, the pulseduration may be characterized by two zero-crossings of a pulse, thewidth of a pulse, or the like.

The magnetic stimulation system may be configured to estimate a timeassociated with two or more peaks of a pulse(s) of a generated signal(e.g., the first peak, the second peak, and/or the third peak of a pulseof a generated signal). For example, the magnetic stimulation system mayestimate a time associated with a first peak and a third peak associatedwith a single pulse of a generated signal (e.g., the first peak 802 andthe third peak 806 as shown in FIG. 8). For example, the magneticstimulation system may estimate a time associated with a first peak anda time associated with a second peak of a generated signal. The magneticstimulation system may determine a pulse duration of the generatedsignal based on the time duration associated with the two or more peaksassociated with the same pulse of the generated signal.

The magnetic stimulation system may determine if a failure has occurredbased on the pulse duration, for example, by checking if the pulseduration is outside of a pulse duration acceptance window. The pulseduration acceptance window may be adjustable based on the settings ofthe type of magnetic stimulation therapy, the magnetic stimulationtreatment parameters, and/or the patient parameters. For example, thepulse duration acceptance window may be 10%, meaning that the pulseduration of the signal may be plus/minus 10% of the expected pulseduration (e.g., as determined in accordance with the expected signal500) to be within the pulse duration acceptance window. For example, thepulse duration acceptance window may be between 300-350 μs. For example,the pulse duration acceptance window may be between 175-275 μs. Forexample, the pulse duration acceptance window may be between 200-250 μs.

The magnetic stimulation system may determine whether a failure hasoccurred based on an average pulse duration of a generated signal (e.g.,signal 800). The magnetic stimulation system may estimate a timeassociated with two or more peaks of a pulse(s) of the generated signal.The two or more peaks may be associated with different pulses of thegenerated signal. The magnetic stimulation system may determine anaverage pulse duration of the two or more pulses of the generated signalusing the time associated with the two or more peaks of a pulse(s) ofthe generated signal. For example, the magnetic stimulation system maydetermine the pulse durations of two or more pulses of the generatedsignal, and using the pulse durations of two or more pulses, themagnetic stimulation system may calculate an average pulse duration ofthe generated signal.

The magnetic stimulation system may determine if a failure has occurredusing the average pulse duration, for example, by checking if theaverage pulse duration is outside of the average pulse durationacceptance window. For example, the average pulse duration acceptancewindow may be 10%, meaning that the average pulse duration of the signalmay be plus/minus 10% of the expected average pulse duration (e.g., asdetermined in accordance with the expected signal 500) to be within theaverage pulse duration acceptance window. For example, the average pulseduration acceptance window may be between 150-250 μs. For example, theaverage pulse duration acceptance window may be between 175-225 μs. Forexample, the average pulse duration acceptance window may be between190-210 μs.

The magnetic stimulation system may determine whether a failure hasoccurred based on a sum of the pulse durations of a signal (e.g., signal800) generated by a sensor. The magnetic stimulation system may estimatea time associated with two or more peaks of a pulse(s) of the generatedsignal. The two or more peaks may be associated with different pulses ofthe generated signal. The magnetic stimulation system may determine asum of the pulse durations of the two or more pulses of the generatedsignal using the time associated with the two or more peaks of thegenerated signal.

The magnetic stimulation system may determine if a failure has occurredusing the sum of the pulse durations, for example, by checking if thesum of the pulse durations is outside of the pulse duration sumacceptance window. For example, the pulse duration sum acceptance windowmay be 10%, meaning that the sum of pulses of the signal may beplus/minus 10% of the expected pulse duration sum (e.g., as determinedin accordance with the expected signal 500) to be within the pulseduration sum acceptance window. For example, the pulse duration sumacceptance window may be between 300-500 μs for two pulses of agenerated signal. For example, the pulse duration sum acceptance windowmay be between 350-450 μs for two pulses of a generated signal. Forexample, the pulse duration sum acceptance window may be between 380-420μs for two pulses of a generated signal.

The magnetic stimulation system may detect a failure based on thestimulation time duration of the pulsing magnetic field. The magneticstimulation system may determine whether a failure has occurred based onthe stimulation time duration of a signal generated by a sensor. Asdescribed herein, the stimulation time duration of a generated signalmay refer to the time between a first peak of a first pulse of a pulseburst and a first peak of a last pulse of the pulse burst of the signal.The magnetic stimulation system may estimate a time associated with apeak (e.g., the first peak) of a first pulse of a pulse burst and a timeassociated with a peak (e.g., the first peak) of a last pulse of thepulse burst. The magnetic stimulation system may determine thestimulation time of the pulse burst of the generated signal using thetime associated with the peak of the first pulse of the pulse burst andthe time associated with the peak of the last pulse of the pulse burstof the signal.

The magnetic stimulation system may determine if a failure has occurredusing the stimulation time, for example, by checking if the stimulationtime is outside of a stimulation time acceptance window. For example,the stimulation time acceptance window may be 10%, meaning that thestimulation time of the signal may be plus/minus 10% of the expectedstimulation time (e.g., as determined in accordance with the expectedsignal 500) to be within the stimulation time acceptance window. Forexample, the stimulation time acceptance window may be between 3.5-4.5s. For example, the stimulation time acceptance window may be between3.9-4.1 s. For example, the stimulation time acceptance window may bebetween 3.95-4.05 s.

The magnetic stimulation system may detect a failure based on the pulseinterval of the pulsing magnetic field. The magnetic stimulation systemmay determine whether a failure has occurred based on the pulse intervalof a generated signal. As described herein, the pulse interval of agenerated signal may refer to the time duration between a first peak ofa pulse of a generated signal and a first peak of a subsequent pulse(e.g., immediately subsequent pulse) of the signal. For example, thepulse interval of a generated signal may refer to the number of pulsesper second associated with the pulsing magnetic field.

For example, the magnetic stimulation system may estimate a timeassociated with a peak (e.g., the first peak) of a pulse of thegenerated signal and a time associated with a peak (e.g., the firstpeak) of a subsequent pulse of the generated signal. For example, thepulse and the subsequent pulse may be consecutive pulses in a pulseburst of the generated signal. The magnetic stimulation system maydetermine the pulse interval of the generated signal using the timeassociated with the peak of the pulse of the generated signal and a timeassociated with the peak of the subsequent pulse of the generatedsignal.

The magnetic stimulation system may determine if a failure has occurredusing the pulse interval, for example, by checking if the pulse intervalis outside of a pulse interval acceptance window. For example, the pulseinterval acceptance window may be 10%, meaning that the pulse intervalof the signal may be plus/minus 10% of the expected pulse interval(e.g., as determined in accordance with the expected signal 500) to bewithin the pulse interval acceptance window. For example, the pulseinterval acceptance window may be between 225-475 μs. For example, thepulse interval acceptance window may be between 250-450 μs. For example,the pulse interval acceptance window may be between 300-400 μs.

The magnetic stimulation system may detect a failure based on thestimulation interval of the pulsing magnetic field. The magneticstimulation system may determine whether a failure has occurred based onthe stimulation interval of a signal generated by a sensor. As describedherein, the stimulation interval of a generated signal may be indicativeof the time duration between a first peak of a last pulse of a pulseburst and a first peak of a first pulse of a subsequent (e.g., immediatesubsequent) pulse burst of the signal. The magnetic stimulation systemmay estimate a time associated with a peak (e.g., the first peak) of alast pulse of a pulse burst and a time associated with a peak (e.g., thefirst peak) of a first pulse of a subsequent pulse burst. For example,the pulse burst and the subsequent pulse burst may be consecutive pulsebursts of the generated signal. The magnetic stimulation system maydetermine the stimulation interval of the generated signal using thetime associated with the peak of the first pulse of the pulse burst andthe time associated with the peak of the first pulse of the subsequentpulse burst of the signal.

The magnetic stimulation system may determine if a failure has occurredusing the stimulation interval, for example, by checking if thestimulation interval is outside of a stimulation interval acceptancewindow. For example, the stimulation interval acceptance window may be10%, meaning that the stimulation interval of the signal may beplus/minus 10% of the expected stimulation interval (e.g., as determinedin accordance with the expected signal 500) to be within the stimulationinterval acceptance window. For example, the stimulation intervalacceptance window may be between 3-17 s. For example, the stimulationinterval acceptance window may be between 6-14 s. For example, thestimulation interval acceptance window may be between 9-10 s.

The magnetic stimulation system may detect a failure based on the pulserepetition rate of the pulsing magnetic field. The magnetic stimulationsystem may determine whether a failure has occurred based on the pulserepetition rate of a signal generated by a sensor. As described herein,the pulse repetition rate of a generated signal may be indicative of thenumber of pulses per time duration (e.g., pulses per second (pps)). Themagnetic stimulation system may estimate times associated with a numberof peaks over a predefined period of time (e.g., one second) todetermine the pulse repetition rate of a generated signal.

The magnetic stimulation system may determine if a failure has occurredusing the pulse repetition rate, for example, by checking if the pulserepetition rate is outside of a pulse repetition rate acceptance window.For example, the pulse repetition rate acceptance window may be 10%,meaning that the pulse repetition rate of the signal may be plus/minus10% of the expected pulse repetition rate (e.g., as determined inaccordance with the expected signal 500) to be within the pulserepetition rate acceptance window. For example, the pulse repetitionrate acceptance window may be between 3-40 pps. For example, thestimulation interval acceptance window may be between 5-30 pps. Forexample, the stimulation interval acceptance window may be between 10-20pps.

The magnetic stimulation system may detect a failure by measuring and/orestimating a rolling average value and/or a weighted average value of agenerated signal associated with a pulsing magnetic field. For example,the magnetic stimulation system may determine that a failure hasoccurred if the rolling average and/or a weighted average one or morepulse sets deviate by more than a threshold or percentage. The thresholdor percentage may be predetermined, fixed, and/or adjustable. Forexample, the threshold or percentage may be adjustable based on thesettings of the type of magnetic stimulation therapy, the magneticstimulation treatment parameters, and/or the patient parameters. Themagnetic stimulation system may take larger samples of the pulsingmagnetic field and detect the failure over a greater sample size thanusing just one or two peaks of a pulse of the pulsing magnetic field.

As described herein, the magnetic stimulation system may include amagnetic stimulation component that may generate a pulsing magneticfield for a magnetic stimulation procedure. The magnetic stimulationsystem may estimate average values for pulse sets of the generatedsignal. For example, an average value for a corresponding set of pulsesmay be an average maximum voltage of the set of pulses, an averageminimum voltage of the set of pulses, an average time duration of theset pulses, an average time per pulse of the set of pulses, and/or anaverage decay rate per pulse of the set of pulses. For example, anaverage value for a corresponding pulse set may include an averagemaximum voltage of one or more peaks of the pulses of the pulse set, orthe like. The average values may be weighted averages or unweightedaverages.

For example, two average values of two pulse sets may be estimated. Thefirst average value may be associated with a first set of pulses of thepulsing magnetic field. The first set of pulses of the pulsing magneticfield may include two or more pulses, which may or may not be part ofthe same pulse burst of the pulsing magnetic field. The second averagevalue may be associated with a second set of pulses of the pulsingmagnetic field. The second set of pulses of the pulsing magnetic fieldmay include two or more pulses, which may or may not be part of the samepulse burst of the pulsing magnetic field. The first set of pulses andthe second set of pulses may be associated with the same pulse burst ofdifferent pulse bursts of the pulsing magnetic field. The first set ofpulses and the second set of pulses may include one or more of the samepulses. The first average value and the second average value may or maynot relate to the same characteristic of the generated signal. Althoughdescribed with reference to a first and second average value, themagnetic stimulation system may utilize any number of average values todetermine a failure associated with a pulsing magnetic field.

The magnetic stimulation system may determine whether a failure occurredbased on the estimated first average value and the estimated secondaverage value. For example, the failure may be determined to haveoccurred when the first average value and the second average valuedeviate by more than a threshold or percentage. For example, the failuremay be determined to have occurred when the first average value and thesecond average value deviate by more than a rolling average acceptancewindow (e.g., which may be 10%).

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, UE, terminal, base station, RNC, or any host computer.

What is claimed is:
 1. A system for monitoring a pulsing magnetic fieldrelated to magnetic stimulation therapy, the system comprising: amagnetic stimulation component configured to generate the pulsingmagnetic field for the magnetic stimulation therapy; a sensor configuredto generate a signal associated with the pulsing magnetic field, thesignal comprising a plurality of peaks; and a processor configured to:estimate a first characteristic associated with a first peak of thesignal; estimate a second characteristic associated with a second peakof the signal; determine a third characteristic of the signal based onthe first characteristic and the second characteristic; and determinewhether a failure occurred based on the third characteristic of thesignal.
 2. The system of claim 1, wherein the first characteristiccomprises at least one of a voltage of the first peak, a current of thefirst peak, an RMS value of the first peak, a zero-cross of the firstpeak, a time value of the first peak, or a time duration of the firstpeak, and wherein the second characteristic comprises at least one of avoltage of the second peak, a current of the second peak, an RMS valueof the second peak, a zero-cross of the second peak, a time value of thesecond peak, or a time duration of the second peak.
 3. The system ofclaim 1, wherein the third characteristic comprises one or more of adecay rate of the signal, a frequency of the signal, a timing associatedwith the signal, a magnetic flux associated with the signal, or acurrent associated with the signal.
 4. The system of claim 1, whereinthe signal comprises one or more of a voltage proportional to a changein the pulsing magnetic field or a current proportional to a change inthe pulsing magnetic field.
 5. The system of claim 1, wherein a pulse ofthe pulsing magnetic field is associated with a plurality of peaks, andwherein the first peak and the second peak are associated with the samepulse of the pulsing magnetic field.
 6. The system of claim 1, whereinthe first peak is associated with a first pulse of the pulsing magneticfield and the second peak is associated with a second pulse of thepulsing magnetic field.
 7. The system of claim 1, wherein the thirdcharacteristic is an average of the first characteristic and the secondcharacteristic, and wherein the failure is determined to have occurredwhen the average is outside of an acceptance window.
 8. The system ofclaim 7, wherein the acceptance window is dependent upon one or moresettings of the magnetic stimulation therapy.
 9. The system of claim 1,wherein: the first characteristic is a pulse shape associated with thefirst peak, a pulse time associated with the first peak, a pulseamplitude associated with the first peak, or a pulse duration associatedwith the first peak; the second characteristic is a pulse shapeassociated with the second peak, a pulse time associated with the secondpeak, a pulse amplitude associated with the second peak, or a pulseduration associated with the second peak; the third characteristic is afunction of the first characteristic and the second characteristic; andthe failure is determined to have occurred when the third characteristicis outside of a predetermined acceptance window.
 10. The system of claim1, wherein the first peak is characterized by a first positive voltageand the second peak is characterized by a second positive voltageassociated with the same pulse, wherein the third characteristic is atime between the first peak and the second peak, and wherein the failureis determined to have occurred when the time between the first peak andthe second peak is outside of a pulse duration acceptance window. 11.The system of claim 1, wherein the third characteristic comprises anaverage pulse duration of the pulsing magnetic field, and the failure isdetermined to have occurred when the average pulse duration is outsideof an average pulse duration acceptance window.
 12. The system of claim1, wherein the third characteristic comprises a sum of pulse duration ofthe pulsing magnetic field, and the failure is determined to haveoccurred when the sum of pulse duration is outside of a pulse durationsum acceptance window.
 13. The system of claim 1, wherein the first peakand the second peak are associated with a same pulse of the pulsingmagnetic field, wherein the third characteristic comprises a voltageratio between the first peak and the second peak, and wherein thefailure is determined to have occurred when the voltage ratio is outsideof a decay ratio acceptance window.
 14. The system of claim 1, whereinthe first peak and the second peak are associated with a same pulse ofthe pulsing magnetic field, wherein the third characteristic comprises avoltage difference between the first peak and the second peak, andwherein the failure is determined to have occurred when the voltagedifference is outside of a peak-to-peak acceptance window.
 15. Thesystem of claim 1, wherein the third characteristic comprises a voltageof the first peak or the second peak, and wherein the failure isdetermined to have occurred when at least one of the first peak and thesecond peak is outside of an amplitude acceptance window.
 16. The systemof claim 1, wherein the first characteristic comprises a first voltageof the first peak, the second characteristic comprises a second voltageof the second peak, and the third characteristic comprises an averageamplitude indicative of average voltage amplitudes of the first andsecond peaks, and wherein the failure is determined to have occurredwhen the average voltage amplitude is outside of an average amplitudeacceptance window.
 17. The system of claim 1, wherein the first peak andthe second peak are associated with a same pulse of the pulsing magneticfield, wherein the first characteristic comprises a voltage of the firstpeak, wherein the third characteristic comprises a peak to RMS voltageratio associated with a pulse of the pulsing magnetic field, and whereinthe failure is determined to have occurred when a ratio between thevoltage of the first peak and the peak to RMS voltage ratio fallsoutside of a peak to RMS voltage acceptance window.
 18. The system ofclaim 17, wherein the peak to RMS voltage acceptance window ischaracterized by a shape of the peak to RMS voltage.
 19. The system ofclaim 1, wherein the first peak is associated with a first pulse of apulse burst of the pulsing magnetic field and the second peak isassociated with a last pulse of the pulse burst of the pulsing magneticfield, wherein the third characteristic comprises a stimulation timeindicative of a time duration between the first peak and the secondpeak, and wherein the failure is determined to have occurred when thestimulation time is outside a stimulation time duration acceptancewindow.
 20. The system of claim 1, wherein the first peak is associatedwith a first pulse of a pulse burst of the pulsing magnetic field andthe second peak is associated with a second pulse of the pulse burst ofthe pulsing magnetic field, wherein the third characteristic comprises apulse interval indicative of a time between the first peak and thesecond peak, and wherein the failure is determined to have occurred whenthe pulse interval is outside of a pulse interval acceptance window. 21.The system of claim 20, wherein the first pulse and the second pulse areconsecutive pulses of the pulsing magnetic field.
 22. The system ofclaim 1, wherein the first peak is associated with a last pulse of afirst pulse burst of the pulsing magnetic field and the second peak isassociated with a first pulse of a second pulse burst of the pulsingmagnetic field, wherein the first pulse burst and the second pulse burstare consecutive pulse bursts, wherein the third characteristic comprisesa stimulation interval indicative of a time duration between the firstpeak and the second peak, and wherein the failure is determined to haveoccurred when the stimulation interval is outside of a stimulationinterval acceptance window.
 23. The system of claim 1, wherein the firstpeak and the second peak are associated with a same pulse of the pulsingmagnetic field, wherein the first peak is characterized by a negativevoltage, wherein the third characteristic comprises a peak duration ofthe first peak, and wherein the failure is determined to have occurredwhen the peak duration of the first peak is outside of a peak durationacceptance window.
 24. The system of claim 1, wherein the processor isfurther configured to receive settings of the magnetic stimulationtherapy procedure and compare the settings of the magnetic stimulationtherapy procedure with the third characteristic to determine whether thefailure has occurred.
 25. The system of claim 1, further comprising anindicator configured to indicate when the failure has occurred.
 26. Thesystem of claim 1, wherein the sensor comprises at least one of aconductive coil, a loop having a number of turns based on the pulsingmagnetic field, a Hall sensor, a magnetoresistive material, a Faradayeffect sensor, a Kerr effect sensor, a flux gate sensor, an inductancechange element, a nerve tissue response measurement device, or anelectric field sensor in a conductive field.
 27. The system of claim 1,wherein the processor is further configured to perform at least one of:pause the magnetic stimulation therapy procedure, shut down the magneticstimulation system, alert a user of the magnetic stimulation system, oralter a current applied to the magnetic stimulation component.
 28. Thesystem of claim 1, wherein the processor is further configured to log atleast one of the first characteristic, the second characteristic, thethird characteristic, or the failure.
 29. The system of claim 1, whereinthe magnetic stimulation component comprises a plurality of treatmentcoils.
 30. The system of claim 29, wherein the sensor is configured togenerate a plurality of signals associated with the pulsing magneticfield.
 31. A system for monitoring a magnetic field related to atranscranial magnetic stimulation (TMS) procedure, the systemcomprising: a magnetic stimulation component configured to generate apulsing magnetic field for the TMS procedure, wherein the pulsingmagnetic field is characterized by a plurality of pulses; a sensorconfigured to generate a voltage induced by a change in the pulsingmagnetic field; and a processor configured to: estimate a first averagevalue of the voltage, the first average value being associated with afirst set of pulses of the plurality of pulses; estimate a secondaverage value of the voltage, the second average value being associatedwith a second set of pulses of the plurality of pulses; and determinewhether a failure occurred by comparing the estimated first averagevalue and the estimated second average value.
 32. The system of claim31, wherein the first average value and the second average value areweighted averages.
 33. The system of claim 31, wherein the first averagevalue and the second average value are unweighted averages.
 34. Thesystem of claim 31, wherein the first average value comprises at leastone of: (1) a first average maximum voltage of the first set of pulses;(2) a first average minimum voltage of the first set of pulses; (3) afirst average time duration of the first set of pulses; (4) a firstaverage time per pulse of the first set of pulses; or (5) a firstaverage decay rate per pulse of the first set of pulses; and wherein thesecond average value comprises at least one of: (1) a second averagemaximum voltage of the second set of pulses; (2) a second averageminimum voltage of the second set of pulses; (3) a second average timeduration of the second set of pulses; (4) a second average time perpulse of the second set of pulses; or (5) a second average decay rateper pulse of the second set of pulses.
 35. The system of claim 31,wherein the failure is determined to have occurred when the firstaverage value and the second average value deviate by more than athreshold or percentage.